Bhat Gandhinagar ADITYA Upgradation with Divertor Configuration Contributions from Deepti Sharma Equilibrium study IPREQ Richa Bandyopadhyay Transport simulation TSC ID: 1025503
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1. R. SrinivasanInstitute for Plasma Research,Bhat, GandhinagarADITYA Upgradation with Divertor ConfigurationContributions from:Deepti Sharma – Equilibrium study (IPREQ)Richa Bandyopadhyay – Transport simulation (TSC)Himabindu and Anil Tyagi – Divertor study (SOLPS)
2. Central solenoidToroidal Field coils- for main confining fieldPoloidal coils – for plasma shaping & control PlasmaTypical Tokamak Tokamak is an Axisymmetric torus with Toroidal magnetic field produced by external coils and poloidal field produced by toroidal plasma current and external coils.Both fields are necessary to confine charged particles or plasmas.
3. Limiter & Divertor ConfigurationsIn limiter plasma, the plasma is limited by a solid surface where as in divertor configuration, the plasma is confined within the Last Closed Flux Surface (LCFS). Beyond LCFS, the field lines are open and fall on the divertor plate. Divertor is needed for steady state operation Shaping of plasma (elongation, traingularity) achieved with external coils, and shaping helps in achieving H-mode plasmas easier. Proposal for the upgrade involves the implementation of a divertor plasma with shaping capabilities
4. -- elongation & -- triangularity.B=0
5. Original Aditya Tokamak: Machine Parameter:Rectangular Vessel.Major Radius : 75cm Minor Radius : 25cmToroidal field : .75-1.0T Plasma Parameter Plasma current : 100 kAElectron density : ~1013 cm-3Electron Temp ~ 400eV
6. Original Aditya equilibrium configuration 2 pairs of coils BV1 (60 turns); 2 pairs of coils BV2 (22 turns) connected in series with different number of turns.BV1BV2R(m)0.3761.634Z(m)±1.05±1.19R(m)0.1640.18Z(m)0.1150.038NI(MA)-0.128-0.065
7. Constraints involved in ADITYA-UDown time of the device should not be more than 2 yearsRefurbish the existing TF coils and this limits the vessel boundaryExisting power supplies and ohmic & vertical field coils to be usedAdditional coils compatible with existing ones to be used to vary the plasma shape (limited shape flexibility) Space available for additional coils limited by new vessel and existing TF coils Limits the divertor coil current and this limits the plasma current for divertor configuration
8. Possible divertor coil positionsNew circular vacuum vessel with diameter of 60cm. D1 & D2 are two pair of symmetric diverter coilsBV1BV2D1D2R(m)0.3761.6430.4601.075Z(m)±1.05±1.190.2950.333R(m)0.1640.180.050.05Z(m)0.1150.0380.050.05NI(MA)-0.288-0.1050.1500.150
9. Aditya Divertor ConfigurationTo provide operational flexibility, Aditya is Upgraded from circular plasma to X-point plasma.Old BV1, BV2 coils have to be fed independently.D1 & D2 are two pairs of poloidal field coils (divertor coils) with current limit of 150KAt.Rectangular vessel is converted into circular vessel with diameter 60cm.Divertor coils are positioned at the available space. Plasma Parameter for Upgradation case: Plasma current : 100 kA Electron density : ~1013 cm-3Electron Temp ~ 400eVBtor = 1.5T
10. IPREQ: Plasma equilibrium studyTokamak Equilibrium code IPREQEquilibrium ReconstructionPF DESIGN CODE FOR TOKAMAKS (Single/Double null plasmas with strike point constraint)MHD stability analysis with stability codes like ERATO, PEST2IPREQ used to obtain optimized design of ADITYA-U divertor configuration SST-1 PF design with IPREQ
11. Double Null Configuration low pEquilibrium case -1(D2=0kA)
12. Equilibrium case -2 (D2=8kA)
13. Equilibrium case -3
14. Comparison of equilibrium case 1 &3
15. Parameters of ADITYA-U DN Low p Case-1Case-2Case-3BV1-136kA-136kA-136kABV2-50kA-50kA-50kAD1150kA150kA100kAD20kA8kA0kAp0.020.020.02R0 (cm) 70.277.672.1A(cm)14.519.117.7Vol0.390.670.561.3471.131.224I0.971.081.01If possible to move D1 little outward, it would have given more flexibility in terms of plasma current
16. Case-1Case-2Case-3BV1-136kA-136kA-136kABV2-50kA-50kA-50kAD1150kA150kA100kAD20kA4kA0kAp0.290.290.29R0 (cm) 72.576.875.1A(cm)15.818.519.9Vol0.460.620.701.261.151.12i1.041.131.14 Parameters of ADITYA-U high p
17. High p equilibrium case -1
18. High p equilibrium case -2
19. High p equilibrium case -3
20. Single null equilibrium caseSingle nullBV1-98kA/-68kABV2-47kA/-98kAD1120kA/150kAD210kA/9kAp0.02R0 (cm) 75.8A(cm)17.1Vol0.531.05i0.87
21. Predictive Simulation of ADITYA-U using TSC Initial and target plasma equilibrium is prescribedPlasma density profile is fixed Ohmic system with current feedback is used to achieve the prescribed plasma current evolutionVessel and other passive elements are modeled and eddy current impact on plasma evolution is takenProvides the evolution of plasma from circular to diverted configuration as well as ramp up to ramp down scenario.Shows the stable path of plasma evolution
22. ADITYA-U Coil SystemCoil Labeled 6 are the Ohmic Coils. TR1 , TR2, TR3, TR4 and TR5 corresponds to ohmic systemPlasma current feedback is given through a PID controller on the Ohmic Transformer current.
23. Aditya-U Plasma evolution in TSC1234567t=0, Ip=10kA21ms, Ip=39kA 62ms, Ip=94kA107ms, Ip=100kA197ms, Ip=100kA247ms, Ip=53kA290ms, Ip=10kA2345671Ip (A)Te (eV)
24. TSC Output
25. Coil Currents
26. Confinement Time
27. Preliminary study of ADITYA-U divertor using SOLPS Double null plasma equilibrium with actual divertor plate is usedThe core edge interface density is fixed at 1 x 1019 m-3Input power is taken as 200 kW (only ohmic, no auxiliary heating is considered)Cross-field diffusivities assumedComputational domain extended over the entire vesselThe peak heat load obtained at the divertor plate is about 1 MW/m2
28. (1) Aditya DN Equilibrium 2) Grid nx X ny =114 X 20
29. Mid-planes profiles of density and temperatureInner-miplane Outer-midplane
30. Heat flux profiles on the divertor targets
31. ConclusionADITYA-U can produce double and single-null plasma confugurationPlasma radius of 15 to 20 cm, nominal elongation but with strong triangularity can be achievedDivertor configuration can be produced with 100 kA plasma. For higher plasma current, auxiliary divertor coils will be usedThe preliminary study shows that the expected heat load on divertor is about 1 MW/m2 which is twice the SST-1 heat load and 1/10th of ITER steady state heat load. With auxiliary heating power, one can have higher heat load at the divertor plateThese experiments will be carried out in coming years
32. Thank you